Add directory_entry.cc to libppapi_cpp

Add directory_entry.cc to libppapi_cpp

I believe FileRef::ReadDirectoryEntries is the one depends on it.

BUG=
R=binji@chromium.org, sbc@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=203995

[victorhsieh, 2013-06-03 17:33:58]

PTAL

[Sam Clegg, 2013-06-03 18:07:04]

On 2013/06/03 17:33:58, victorhsieh wrote:
> PTAL

Do we not have any code in the SDK that uses FileRef::ReadDirectoryEntries yes?

If we do then presumably it should be failing right now, if not then maybe we
should
land the code  that uses this at the same time, so we get some testing (at least
compile testing)?

[binji, 2013-06-03 18:16:42]

On 2013/06/03 18:07:04, Sam Clegg wrote:
> On 2013/06/03 17:33:58, victorhsieh wrote:
> > PTAL
> 
> Do we not have any code in the SDK that uses FileRef::ReadDirectoryEntries
yes?
> 
> If we do then presumably it should be failing right now, if not then maybe we
> should
> land the code  that uses this at the same time, so we get some testing (at
least
> compile testing)?

nacl_io uses the PPAPI C interface, so doesn't fail. The only other example is
file_io, but it doesn't currently do anything with directories. It should be
extended to do so, but I don't think we should hold up landing this change for
it. I've filed http://crbug.com/246269

[victorhsieh, 2013-06-03 18:17:36]

What kind of test do you mean?  pp::FileRef::ReadDirectoryEntries is tested in
ppapi/tests/test_file_ref.cc.  Does naclsdk test it or it has additional test
cases?

[victorhsieh, 2013-06-03 18:18:16]

On 2013/06/03 18:17:36, victorhsieh wrote:
> What kind of test do you mean?  pp::FileRef::ReadDirectoryEntries is tested in
> ppapi/tests/test_file_ref.cc.  Does naclsdk test it or it has additional test
> cases?

Ah, race condition.

[Sam Clegg, 2013-06-03 18:46:09]

On 2013/06/03 18:18:16, victorhsieh wrote:
> On 2013/06/03 18:17:36, victorhsieh wrote:
> > What kind of test do you mean?  pp::FileRef::ReadDirectoryEntries is tested
in
> > ppapi/tests/test_file_ref.cc.  Does naclsdk test it or it has additional
test
> > cases?
> 
> Ah, race condition.

I see, I was thinking nacl_io was the consumer of this interface but it uses the
C interface.

I'm little nervous about adding a new .cc file a library without any code that
references it in the SDK (for example, if there was an implicit dependency on
another .cc file that was missing from this CL we won't know until some code
references this for for the first time).

I'll go with Ben on this though...as long as that file i/o example change in the
works then this LGTM I guess.

[victorhsieh, 2013-06-03 21:36:13]

Added an example for ReadDirectoryEntries.

[Sam Clegg, 2013-06-03 22:13:20]

On 2013/06/03 21:36:13, victorhsieh wrote:
> Added an example for ReadDirectoryEntries.

Thanks victor!  Much appreciated.

Still looks good to me, but I'd like to get an LG from Ben who is the original
author of this example.

What happens then you run this example on an older chrome, does it fail
gracefully?

[victorhsieh, 2013-06-03 22:29:47]

When it runs in older version, I think it's going to hit this line
(https://code.google.com/p/chromium/codesearch#chromium/src/ppapi/cpp/file_ref...)
and call the callback directory with result == PP_ERROR_NOINTERFACE.  So "List
failed" should appear on the page.

[binji, 2013-06-04 17:29:47]

lgtm, thanks!

[victorhsieh, 2013-06-04 17:33:25]

Committed patchset #3 manually as r203995 (presubmit successful).